Abstract # 74:

Scheduled for Thursday, June 21, 2007 05:00 PM-07:00 PM: Session 7 (South Main Hall) Poster Presentation

Measuring Lateral Biases during Feeding in Semifree-Ranging Black and White Ruffed Lemurs (Varecia variegata variegata)

E. L. Nelson1,2, F. Ruperti1,3 and M. A. Novak2,4
1Monkeyland Primate Sanctuary, Plettenberg Bay, South Africa, 2Neuroscience and Behavior Graduate Program, University of Massachusetts Amherst, Amherst, MA 01003 USA, 3Primate Conservation Postgraduate Programme, Oxford Brookes University, Oxford, United Kingdom, 4Department of Psychology, University of Massachusetts Amherst, Amherst, MA 01003 USA
     Behavioral laterality is often studied in nonhuman primates in the context of feeding. Researchers have primarily been concerned with manual laterality, or asymmetries in the use of the hands. In a species such as the black and white ruffed lemur (Varecia variegata variegata) that has a propensity to feed with the mouth, behavioral asymmetries in feeding may be more subtle. Varecia have been observed to tilt their heads back while chewing, often at a sharp angle to the left or right side. This study was the first to examine the relationship between head-tilt and hand use during feeding in Varecia. Data were collected from a semifree-ranging population (n=11) at Monkeyland Primate Sanctuary in South Africa. Primates were provisioned twice daily at 12 feeding platforms scattered throughout the forest enclosure. Varecia were videotaped feeding between 0730 and 1730 hours. Sampling was based on spontaneous observation and consisted of focal-animal follows until the individual moved out of sight. A one-sample t-test of hand use revealed a significant group-level left bias [t(10)=-4.04, p<0.01]. This is consistent with previous literature in Varecia. There was no group-level bias for head-tilt, although five individuals showed concordance in hand use and head-tilt. This is in contrast to studies of human neonates that have found a rightward bias in head turning which corresponds to a right-hand preference for reaching later in life.